Category: SDN

It’s hard to visit an IT journal web site without stumbling upon an SDN fairy tale. Here’s another one:

The idea is to cut away the manual process of setting up new firewalls, load balancers and other network appliances, and instead open the door to provisioning a new network infrastructure within a few minutes.

And why exactly is it that you can’t do that today?

Gartner has updated their networking hype cycle. Not surprisingly:

• Ethernet switching fabrics are on the slope of enlightenment (finally – we’ve been educating networking engineers on what they really are for half a decade);
• SDN is well on its way into the trough of disillusionment (shameless plug: I guess not enough people attended real-life SDN workshops) and whitebox switching is going the same way;
• SD-WAN is nearing the peak of inflated expectations;
• FCoE and Long-Distance vMotion will be dead before they reach the plateau.

Gartner won’t give you free access to the graph, but you’ll find it in an article published on The Register.

One of the participants of the Carrier Ethernet LinkedIn group asked a great question:

When we install a virtual-router of any vendor over an ordinary sever (having general-purpose microprocessor), can it really compete with a physical-router having ASICs, Network Processors…?

Short answer: No … and here’s my longer answer (cross-posted to my blog because not all of my readers participate in that group).

Matt Oswalt wrote a great blog post complaining about vendors launching ocean-boiling solutions instead of focused reusable components, and one of the comments his opinion generated was along the lines of “I thought one of the reasons people wanted SDN, is because they wanted to deal with The Network – think about The Network's Performance, Robustness and Services instead of dealing with 100s or 1000s of individual boxes.”

The comment is obviously totally valid, so let me try to reiterate what Matt wrote using Lego bricks ;)

Last week I published slide decks for Network Function Virtualization, BGP-Based SDN Solutions and SDN Use Cases webinars – they’re available to subscribers and attendees registered for individual webinars.

Content from all three webinars is part of my SDN workshop – if you’d like to hear a live explanation, register for one of them.

My Business Case for SD-WAN blog post received numerous comments pointing out the potential pitfalls of hybrid WAN, including reduced security, unreliable Internet services and denial-of-service attacks.

While all those comments are perfectly valid, I still think hybrid WAN (whether implemented with traditional technologies or SD-WAN products) makes perfect sense.

Most people casually involved with virtual appliances and network function virtualization (NFV) believe that replacing Linux TCP/IP stack with user-mode packet forwarding (example: Intel’s DPDK) boosts performance from meager 1 Gbps to tens of gigabits (and thus makes hardware forwarding obsolete).

Having data points is always better than having opinions; today let’s look at Receiving 1 Mpps with Linux TCP/IP Stack blog post.

2015-07-18: The blog post was updated based on feedback by Kristian Larsson.

An anonymous commenter wrote this comment to my initial SD-WAN post:

I can still hardly imagine the business case behind SD-WAN. Any thoughts?

This question is really easy to answer. There’s a huge business case that SD-WAN products are aiming to solve: replacing traditional MPLS/VPN networks with encrypted transport over public Internet. However…

After I wrote a comment on a LinkedIn discussion in the Carrier Ethernet group (more details here), Vishal Sharma wrote an interesting response, going into more details of distinction between centralized control and centralized control plane.

One of the Software Defined Evangelists has declared 2015 as the Year of SD-WAN, and my podcast feeds are full of startups explaining how wonderful their product is compared to the mess made by legacy routers, so one has to wonder: is SD-WAN really something fundamentally new, or is it just another old idea in new clothes?